19-2535; Rev 1; 12/05
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
The MAX6439–MAX6442 are a family of ultra-low-power
battery monitors with integrated microprocessor (µP)
supervisors. The battery monitors are offered with single or dual low-battery output options that can be used
to signal when the battery is OK (enabling full system
operation), when the battery is low (for low-power system operation), and when the battery is dead (to disable system operation). These devices also have an
independent µP supervisor that monitors VCC and provides an active-low reset output. A manual reset function is available to reset the µP with a push-button. No
external components are required.
The MAX6439–MAX6442 are offered with several factory-trimmed low-battery threshold combinations ideal for
single-cell lithium-ion (Li+) or multicell alkaline/NiCd/
NiMH applications. When the battery voltage drops
below each specified low threshold, the low-battery outputs are asserted to alert the system. When the voltage
rises above the specified high thresholds, the outputs
are deasserted after a 150ms minimum timeout period,
ensuring the voltages have stabilized before power circuitry is activated or providing microprocessor reset timing. The low and high thresholds provide hysteresis in
battery-operated systems to eliminate output chattering.
The MAX6439/MAX6440 offer factory-trimmed battery
monitors with a single output. The MAX6441/MAX6442
offer factory-trimmed battery monitors with dual outputs.
All battery monitors have open-drain low-battery outputs.
The MAX6439–MAX6442 monitor system voltages
(VCC) from 1.8V to 3.3V with seven fixed reset threshold
options. Each device is offered with two minimum reset
timeout periods of 150ms or 1200ms. The MAX6439/
MAX6441 are offered with an open-drain RESET output
and the MAX6440/MAX6442 are offered with a pushpull RESET output.
The MAX6439–MAX6442 are offered in a SOT23 package and are fully specified over a -40°C to +85°C temperature range.
Features
♦ Factory-Trimmed VBATT Threshold Options for
Monitoring Single-Cell Li+ or Multicell
Alkaline/NiCd/NiMH Applications
♦ Immune to Short Battery Voltage Transients
♦ Low Current (2.5µA typ at 3.6V)
♦ Single and Dual Low-Battery Output Options
♦ 150ms Minimum LBO Timeout Period
♦ Independent µP Reset with Manual Reset
♦ Factory-Set Reset Thresholds for Monitoring VCC
from 1.8V to 3.3V
♦ Available with 150ms (min) and 1.2s (min) VCC
Reset Timeout Period Options
♦ -40°C to +85°C Operating Temperature Range
♦ Small 6- and 8-Pin SOT23 Packages
♦ No External Components
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX6439UT_ _ _D_-T
-40°C to +85°C
6 SOT23-6
MAX6440UT_ _ _D_-T
-40°C to +85°C
6 SOT23-6
MAX6441KA_ _ _D_-T
-40°C to +85°C
8 SOT23-8
MAX6442KA_ _ _D_-T
-40°C to +85°C
8 SOT23-8
Note: The first two “_ _” are placeholders for the battery monitor voltage levels. Desired threshold levels are set by the part
number suffix found in Tables 1 and 2. The third “_” is the VCC
reset threshold level suffix found in Table 3. The “_” after the D
is a placeholder for the reset timeout period suffix found in
Table 4. All devices are available in tape-and-reel only. There
is a 2500-piece minimum order increment for standard versions. Sample stock is typically held on standard versions only.
Nonstandard versions require a minimum order increment of
10,000 pieces. Contact factory for availability.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Applications
Battery-Powered Systems (Single-Cell Li+ or
Two-/Three-Cell NiMH, NiCd, Alkaline)
Cell Phones/Cordless Phones
Portable Medical Devices
Pin Configurations
TOP VIEW
VBATT 1
MR 2
Electronic Toys
Pagers
MAX6439
MAX6440
LBO 3
6
VCC
5
GND
4
RESET
PDAs
MP3 Players
SOT23-6
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX6439–MAX6442
General Description
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
ABSOLUTE MAXIMUM RATINGS
VBATT, VCC to GND.................................................-0.3V to +6V*
Open-Drain LBO, LBOH, LBOL, LBOLH to GND ...-0.3V to +6V*
Open-Drain RESET to GND ....................................-0.3V to +6V*
Push-Pull RESET to GND............................-0.3V to (VCC + 0.3V)
MR to GND .................................................-0.3V to (VCC + 0.3V)
Input/Output Current, All Pins .............................................20mA
Continuous Power Dissipation (TA = +70°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C)............695mW
8-Pin SOT23 (derate 8.9mW/°C above +70°C)............714mW
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
*Applying 7V for a duration of 1ms does not damage the device.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1)
PARAMETER
VBATT Operating Voltage Range
VCC Operating Voltage Range
VCC + VBATT Supply Current
SYMBOL
VBATT
VCC
CONDITIONS
MIN
TYP
MAX
TA = 0°C to +85°C
1.0
5.5
TA = -40°C to +85°C
1.2
5.5
TA = 0°C to +85°C
1.0
5.5
TA = -40°C to +85°C
1.2
5.5
ICC + IBATT VBATT = 3.6V, VCC = 3.3V, no load (Note 2)
2.5
7
UNITS
V
V
µA
VBATT THRESHOLDS
HTH Threshold
LTH Threshold
2
HTH
LTH
MAX6439UT_ J, MAX6440UT_ J
3.510
3.60
3.690
MAX6439UT_ I, MAX6440UT_ I
3.413
3.50
3.588
MAX6439UT_ H, MAX6440UT_ H
3.315
3.40
3.485
MAX6439UT_ G, MAX6440UT_ G
3.218
3.30
3.383
MAX6439UT_ T, MAX6440UT_ T
2.535
2.60
2.665
MAX6439UT_ S, MAX6440UT_ S
2.438
2.50
2.563
MAX6439UT_ R, MAX6440UT_ R
2.340
2.40
2.460
MAX6439UT_ Q, MAX6440UT_ Q
2.243
2.30
2.358
MAX6439UTF, MAX6440UTF
3.023
3.10
3.178
MAX6439UTE, MAX6440UTE
2.925
3.00
3.075
MAX6439UTD, MAX6440UTD
2.828
2.90
2.973
MAX6439UTC, MAX6440UTC
2.730
2.80
2.870
MAX6439UTB, MAX6440UTB
2.633
2.70
2.768
MAX6439UTA, MAX6440UTA
2.535
2.60
2.665
MAX6439UTP, MAX6440UTP
2.048
2.10
2.153
MAX6439UTO, MAX6440UTO
1.950
2.00
2.050
MAX6439UTN, MAX6440UTN
1.853
1.90
1.948
MAX6439UTM, MAX6440UTM
1.755
1.80
1.845
MAX6439UTL, MAX6440UTL
1.658
1.70
1.743
MAX6439UTK, MAX6440UTK
1.560
1.60
1.640
_______________________________________________________________________________________
V
V
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
(VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1)
PARAMETER
HTH- Threshold
HTH+ Threshold
LTH- Threshold
LTH+ Threshold
SYMBOL
HTH-
HTH+
LTH-
LTH+
MIN
TYP
MAX
MAX6441UT_ J, MAX6442UT_ J
CONDITIONS
3.510
3.600
3.690
MAX6441UT_ I, MAX6442UT_ I
3.413
3.500
3.588
MAX6441UT_ H, MAX6442UT_ H
3.315
3.400
3.485
MAX6441UT_ G, MAX6442UT_ G
3.218
3.300
3.383
MAX6441UT_ T, MAX6442UT_ T
2.535
2.600
2.665
MAX6441UT_ S, MAX6442UT_ S
2.438
2.500
2.563
MAX6441UT_ R, MAX6442UT_ R
2.340
2.400
2.460
MAX6441UT_ Q, MAX6442UT_ Q
2.243
2.300
2.358
MAX6441UT_ J, MAX6442UT_ J
3.686
3.780
3.875
MAX6441UT_ I, MAX6442UT_ I
3.583
3.675
3.767
MAX6441UT_ H, MAX6442UT_ H
3.481
3.570
3.659
MAX6441UT_ G, MAX6442UT_ G
3.378
3.465
3.552
MAX6441UT_ T, MAX6442UT_ T
2.662
2.730
2.798
MAX6441UT_ S, MAX6442UT_ S
2.559
2.625
2.691
MAX6441UT_ R, MAX6442UT_ R
2.457
2.520
2.583
MAX6441UT_ Q, MAX6442UT_ Q
2.355
2.415
2.476
MAX6441UTF, MAX6442UTF
3.023
3.100
3.178
MAX6441UTE, MAX6442UTE
2.925
3.000
3.075
MAX6441UTD, MAX6442UTD
2.828
2.900
2.973
MAX6441UTC, MAX6442UTC
2.730
2.800
2.870
MAX6441UTB, MAX6442UTB
2.633
2.700
2.768
MAX6441UTA, MAX6442UTA
2.535
2.600
2.665
MAX6441UTP, MAX6442UTP
2.048
2.100
2.153
MAX6441UTO, MAX6442UTO
1.950
2.000
2.050
MAX6441UTN, MAX6442UTN
1.853
1.900
1.948
MAX6441UTM, MAX6442UTM
1.755
1.800
1.845
MAX6441UTL, MAX6442UTL
1.658
1.700
1.743
MAX6441UTK, MAX6442UTK
1.560
1.600
1.640
MAX6441UTF, MAX6442UTF
3.174
3.255
3.337
MAX6441UTE, MAX6442UTE
3.071
3.150
3.229
MAX6441UTD, MAX6442UTD
2.969
3.045
3.121
MAX6441UTC, MAX6442UTC
2.867
2.940
3.014
MAX6441UTB, MAX6442UTB
2.764
2.835
2.906
MAX6441UTA, MAX6442UTA
2.662
2.730
2.798
MAX6441UTP, MAX6442UTP
2.150
2.205
2.260
MAX6441UTO, MAX6442UTO
2.048
2.100
2.153
MAX6441UTN, MAX6442UTN
1.945
1.995
2.045
MAX6441UTM, MAX6442UTM
1.843
1.890
1.937
MAX6441UTL, MAX6442UTL
1.740
1.785
1.830
MAX6441UTK, MAX6442UTK
1.638
1.680
1.722
UNITS
V
V
V
V
_______________________________________________________________________________________
3
MAX6439–MAX6442
ELECTRICAL CHARACTERISTICS (continued)
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
150
225
300
ms
LBO, LBOL, LBOH, LBOLH
Timeout Period
tLBOP
VBATT rising above threshold
LBO, LBOL, LBOH, LBOLH
Delay Time
tLBOD
VBATT falling below threshold
LBO, LBOL, LBOH, LBOLH
Output Low
(Open Drain)
LBO, LBOL, LBOH, LBOLH
Output Open-Drain Leakage
Current
VCC Reset Threshold
VOL
ILKG
VTH
100
(VBATT or VCC) ≥ 1.2V, ISINK = 50µA,
asserted low
0.3
(VBATT or VCC) ≥ 1.6V, ISINK = 100µA,
asserted low
0.3
V
(VBATT or VCC) ≥ 2.7V, ISINK = 1.2mA,
asserted low
0.3
(VBATT or VCC) ≥ 4.5V, ISINK = 3.2mA,
asserted low
0.3
Output deasserted
500
MAX64_ _ _ _ _ _ T
3.000
3.075
3.150
MAX64_ _ _ _ _ _ S
2.850
2.925
3.000
MAX64_ _ _ _ _ _ R
2.550
2.625
2.700
MAX64_ _ _ _ _ _ Z
2.250
2.313
2.375
MAX64_ _ _ _ _ _ Y
2.125
2.188
2.250
MAX64_ _ _ _ _ _ W
1.620
1.665
1.710
MAX64_ _ _ _ _ _ V
1.530
1.575
1.620
VCC Reset Hysteresis
VCC falling at 10mV/µs from (VTH + 100mV)
to (VTH - 100mV)
VCC to RESET Delay
VCC to RESET Timeout Period
MR Input Voltage
MR Minimum Pulse Width
tRP
50
µs
150
225
300
MAX64_ _ _ _ _ _ _ D7
1200
1800
2400
VIL
0.3 x VCC
0.7 x VCC
tMPW
1
100
200
MR Pullup Resistance
MR Rising Debounce Period
4
tDEB
ms
V
µs
MR to RESET Delay
tMRP
V
%
MAX64_ _ _ _ _ _ _ D3
VIH
nA
0.3
MR Glitch Rejection
MR Reset Timeout Period
µs
ns
ns
150
225
300
MR to VCC
750
1500
2250
Ω
(Note 3)
150
225
300
ms
_______________________________________________________________________________________
ms
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
(VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1)
PARAMETER
SYMBOL
RESET Output High
(Push-Pull)
VOH
RESET Output Low
VOL
RESET Output Leakage Current
(Open Drain)
CONDITIONS
MIN
TYP
VCC ≥ 1.53V, ISOURCE = 100µA, RESET
deasserted
0.8 x VCC
VCC ≥ 2.55V, ISOURCE = 500µA, RESET
deasserted
0.8 x VCC
MAX
UNITS
V
VCC ≥ 1.0V, ISINK = 50µA, RESET asserted
0.3
VCC ≥ 1.2V, ISINK = 100µA, RESET asserted
0.3
VCC ≥ 2.12V, ISINK = 1.2mA, RESET
asserted
0.3
RESET deasserted
500
V
nA
Note 1: Production testing done at TA = +25°C; limits over temperature guaranteed by design only.
Note 2: The device is powered up by the highest voltage between VBATT and VCC.
Note 3: MR input ignores falling input pulses, which occur within the MR debounce period (tDEB) after a valid MR reset assertion.
This prevents invalid reset assertion due to switch bounce.
Typical Operating Characteristics
(VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, unless otherwise specified. Typical values are at TA = +25°C.)
TOTAL
2
IBATT
1
ICC
0
1.05
1.00
0.95
0.90
-40
-20
0
20
40
TEMPERATURE (°C)
60
80
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
1.015
MAX6439 toc03
MAX6439 toc02
MAX6439 toc01
3
1.10
NORMALIZED LBO TIMEOUT PERIOD
SUPPLY CURRENT (µA)
4
NORMALIZED LBO TIMEOUT PERIOD
vs. TEMPERATURE
NORMALIZED RESET TIMEOUT PERIOD
SUPPLY CURRENT vs. TEMPERATURE
VCC = 3.3V, VBATT = 3.6V
1.010
1.005
1.000
0.995
0.990
0.985
0.980
-40
-20
0
20
40
TEMPERATURE (°C)
60
80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
_______________________________________________________________________________________
5
MAX6439–MAX6442
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, unless otherwise specified. Typical values are at TA = +25°C.)
LBO ASSERTS ABOVE
THIS LINE
100
90
80
70
60
55
50
RESET ASSERTS ABOVE
THIS LINE
45
40
35
30
1.050
100
1000
LOWER TRIP VOLTAGE
1.000
UPPER TRIP VOLTAGE
0.975
0.950
10
100
LTH THRESHOLD OVERDRIVE (mV)
1000
-20
-40
0
VTH THRESHOLD OVERDRIVE (mV)
20
40
TEMPERATURE (°C)
LBO OUTPUT vs. SINK CURRENT
VCC = 3.3V, VBATT = 2.1V
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
MAX6439 toc08
120
MAX6439 toc07
1.050
100
1.025
LBO OUTPUT (mV)
NORMALIZED RESET THRESHOLD
1.025
25
20
10
MAX6439 toc06
MAXIMUM VCC TRANSIENT DURATION (µs)
110
NORMALIZED UPPER (HTH) AND LOWER
(LTH) TRIP VOLTAGES vs. TEMPERATURE
MAX6439 toc05
60
MAX6439 toc04
120
MAXIMUM VCC TRANSIENT DURATION
vs. VTH THRESHOLD OVERDRIVE
NORMALIZED TRIP VOLTAGES
MAXIMUM VBATT TRANSIENT DURATION
vs. LTH THRESHOLD OVERDRIVE
MAXIMUM VBATT TRANSIENT DURATION (µs)
1.000
80
60
40
0.975
20
LBO ASSERTED
0
0.950
-40
-20
0
20
40
60
2
0
80
4
TEMPERATURE (°C)
6
8
10
ISINK (mA)
RESET OUTPUT vs. SINK CURRENT
VCC = 2.1V, VBATT = 3.6V
RESET OUTPUT vs. SOURCE CURRENT
VCC = 3.3V, VBATT = 3.6V
120
MAX6439 toc10
3.50
MAX6439 toc09
140
3.25
100
RESET OUTPUT (V)
RESET OUTPUT (mV)
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
80
60
40
RESET ASSERTED
3.00
2.75
20
0
2.50
0
2
4
6
ISINK (mA)
6
8
10
0
0.5
1.0
1.5
2.0
2.5
3.0
ISOURCE (mA)
_______________________________________________________________________________________
3.5
60
80
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
PIN
MAX6439/
MAX6440
MAX6441/
MAX6442
NAME
FUNCTION
1
1
VBATT
Battery Voltage Input. Input for battery voltage threshold monitors and device power supply
if VBATT is greater than VCC.
2
3
MR
Manual Reset Input, Active-Low, Internal 1.5kΩ Pullup to VCC. Pull low to assert a one-shot
edge-triggered RESET output for the MR reset timeout period. Leave unconnected or
connect to VCC if unused. The MR input is debounced for MR rising edges to prevent false
reset events.
3
—
LBO
Low-Battery Output, Active Low, Open Drain. LBO is asserted when VBATT drops below the
LTH specification and remains asserted until VBATT rises above the HTH specification for at
least 150ms.
Reset Output, Active Low, Push-Pull or Open Drain. RESET changes from high to low when
the VCC input drops below the selected reset threshold and remains low for the VCC reset
timeout period after VCC exceeds the reset threshold. RESET is one-shot edge-trigger
pulsed low for the MR reset timeout period when the MR input is pulled low. RESET is an
open-drain output for the MAX6439/MAX6441, and a push-pull output for the
MAX6440/MAX6442. The push-pull outputs are referenced to VCC. RESET is guaranteed to
be in the correct logic state for VBATT or VCC > 1.0V.
4
5
RESET
5
2
GND
Ground
6
8
VCC
VCC Voltage Input. Input for VCC reset threshold monitor and device power supply if VCC is
greater than VBATT.
—
6
LBOH
Low-Battery Output High, Active Low, Open Drain. LBOH is asserted when VBATT drops
below the HTH- specification. LBOH is deasserted when VBATT rises above the HTH+
specification for at least 150ms.
—
7
LBOL
Low-Battery Output Low, Active Low, Open Drain. LBOL is asserted when VBATT drops
below the LTH- specification. LBOL is deasserted when VBATT rises above the LTH+
specification for at least 150ms.
—
4
LBOLH
Low-Battery Output Low/High, Active Low, Open Drain. LBOLH is asserted when VBATT
drops below the LTH- specification. LBOLH is deasserted when VBATT rises above the
HTH+ specification for at least 150ms.
Detailed Description
The MAX6439–MAX6442 family is available with several
monitoring options. The factory-trimmed thresholds
eliminate the requirement for external components. The
MAX6439/MAX6440 have single low-battery outputs
and the MAX6441/MAX6442 have dual low-battery outputs (see Figure 1a and Figure 1b).
The MAX6439–MAX6442 combine a 1.23V reference
with two comparators, logic, and timing circuitry to provide the user with information about the charge state of
the power-supply batteries. The MAX6441/MAX6442
monitor separate high-voltage and low-voltage thresholds to determine battery status. The output(s) can be
used to signal when the battery is charged, when the
battery is low, and when the battery is empty. Factorytrimmed thresholds are ideal for monitoring single-cell
Li+ or multicell alkaline/NiCd/NiMH power supplies.
When the power-supply voltage drops below the specified low threshold, the low-battery output asserts. When
the voltage rises above the specified high threshold following a 150ms (min) timeout period, the low-battery
output is deasserted. This ensures the supply voltage
_______________________________________________________________________________________
7
MAX6439–MAX6442
Pin Description
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
VBATT
MAX6441
VBATT
MAX6440
LTH
DETECT
LBOL
5%
HYST
LTH
DETECT
R
Q
S
Q
LBO
TIMEOUT
PERIOD
LBOH
LBO
HTH
DETECT
LBO TIMEOUT
PERIOD
HTH
DETECT
5%
HYST
LBOLH
VCC
1.23V
VCC
VCC
VTH
DETECT
RESET
TIMEOUT
PERIOD
1.23V
RESET
RESET
VTH
DETECT
VCC
RESET
TIMEOUT
PERIOD
MR
VCC
MR
Figure 1a. Functional Diagram
Figure 1b. Functional Diagram
has stabilized before power-converter or microprocessor activity is enabled.
These devices also have an independent µP supervisor
that monitors VCC and provides an active-low reset output. A manual reset function is available to allow the
user to reset the µP with a push-button.
low-battery outputs: LBOH, LBOL, and LBOLH. LBOH
asserts when VBATT drops below VHTH- and remains
asserted for at least 150ms after VBATT rises above
VHTH+. LBOL asserts when VBATT drops below VLTHand remains asserted for at least 150ms after VBATT
rises above VLTH+. LBOLH asserts when VBATT drops
below VLTH- and remains asserted for at least 150ms
after VBATT rises above VHTH+ (see Figure 3). For fastrising VBATT input, the LBOL timeout period must complete before the LBOH/LBOLH timeout period begins.
Low-Battery Output
The low-battery outputs are available in active-low
(LBO, LBOL, LBOH, LBOLH), open-drain configurations. The low-battery outputs can be pulled to a voltage independent of VCC or VBATT, up to 5.5V. This
allows the device to monitor and operate from direct
battery voltage while interfacing to higher voltage
microprocessors.
The MAX6439/MAX6440 single-output voltage monitors
provide a single low-battery output, LBO. These fixedthreshold devices assert LBO when VBATT drops below
V LTH and remain asserted for at least 150ms after
VBATT rises above VHTH (see Figure 2). The MAX6441/
MAX6442 triple-output voltage monitors provide three
8
Reset Output
The MAX6439–MAX6442 provide an active-low reset
output (RESET). RESET is asserted when the voltage at
VCC falls below the reset threshold level. Reset remains
asserted for the reset timeout period after VCC exceeds
the threshold. If VCC goes below the reset threshold
before the reset timeout period is completed, the internal timer restarts. The MAX6439/MAX6441 have opendrain reset outputs, while the MAX6440/MAX6442 have
push-pull reset outputs (see Figure 4).
_______________________________________________________________________________________
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
MAX6439–MAX6442
VBATT
HTH
LTH
tLBOP
LBO
tLBOD
tLBOP
Figure 2. Single Low-Battery Output Timing
HTH+
HTH-
VBATT
LTH+
LTH-
LBOL
tD
tLBOP
LBOH
tLBOP
tLBOP
tD
tLBOP
LBOLH
Figure 3. Dual Low-Battery Output Timing
VCC
VTH
GND
SWITCH
BOUNCE
MR
SWITCH
BOUNCE
SWITCH
BOUNCE
SWITCH
BOUNCE
GND
RESET
tRP
tMRP
tMRP
GND
tDEB
tMPW
tDEB
tMPW
Figure 4. RESET Timing Diagram
_______________________________________________________________________________________
9
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
CURRENTLIMITED
AC WALL
ADAPTER
VHTH
VHYST
VBATT
DC/DC CONVERTER
IN
SHDN
LED
OUT
GATE
IN
VLTH
BATT
CHG
tLBOP
MAX1879
PULSE-WIDTH
SELECT INPUT
LBO
TSEL
THERM
1-CELL
Li+
BATTERY
VCC
VBATT
LBOL
MAX6441
MAX6442
GND
LBOH
LBOLH
ADJ
RESET
HTH = BATTERY VOLTAGE GOOD, ENABLE OPERATION.
LTH = BATTERY VOLTAGE LOW, SUSPEND/DISABLE OPERATION.
GND
THERMISTOR
Figure 5. Hysteresis
Figure 6. Li+ Charger Application (Using MAX1879)
IN
Li+
3.6V
DC/DC
SHDN
OUT
LBOL
VCC
VBATT
LBOH
MAX6441
MAX6442
VCC
NMI
Hysteresis
µP
MR
RESET
GND
logic levels, open-drain/open-collector outputs, or a
momentary push-button switch to GND (the MR function
is internally debounced for the tDEB timeout period) to
create a manual reset function. If MR is driven from long
cables, or if the device is used in a noisy environment,
connect a 0.1µF capacitor from MR to GND to provide
additional noise immunity (see Figure 4).
RESET
GND
Hysteresis increases the comparator’s noise margin by
increasing the upper threshold or decreasing the lower
threshold. The hysteresis prevents the output from
oscillating (chattering) when VBATT is near the low-battery threshold. This is especially important for applications where the load on the battery creates significant
fluctuations in battery voltages (see Figure 5).
Applications Information
Li+ Battery Charger Application
Figure 7. DC-to-DC Converter Application
Manual Reset
Many microprocessor-based products require manual
reset capability, allowing the operator, a test technician,
or external logic circuitry to initiate a reset while the
monitored supplies remain above their reset thresholds.
These devices have a dedicated active-low MR pin.
When MR is pulled low, RESET asserts a one-shot low
pulse for the MR reset timeout period. The MR input has
an internal 1.5kΩ pullup resistor to VCC and can be left
unconnected if not used. MR can be driven with CMOS-
10
The MAX6441/MAX6442 dual-output battery monitors
can be used in conjunction with a battery charger to
provide a system with additional information about the
battery charge state. Many battery chargers, such as
the MAX1879, provide the user with a CHG output,
which tells the system when the battery is charged. The
MAX6441/MAX6442 dual-output battery monitors provide three outputs, which can be used to relay the battery condition to the system. This information is useful in
determining which system resources can be powered by
the battery at the current charge state (see Figure 6).
______________________________________________________________________________________
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
VOLTAGES
2.6V
LOWER
THRESHOLD
(LTH)
UPPER THRESHOLD (HTH)
3.3V
3.4V
3.5V
3.6V
AG
AH
AI
AJ
2.7V
BG
BH
BI
BJ
2.8V
CG
CH
CI
CJ
2.9V
DG
DH
DI
DJ
3.0V
EG
EH
EI
EJ
3.1V
FG
FH
FI
FJ
Table 2. Factory-Trimmed Lower and Upper Threshold Combinations for Two-Cell
Alkaline/NiCd/NiMH Applications
VOLTAGES
LOWER
THRESHOLD
(LTH)
UPPER THRESHOLD (HTH)
2.3V
2.4V
2.5V
2.6V
1.6V
KQ
KR
KS
KT
1.7V
LQ
LR
LS
LT
1.8V
MQ
MR
MS
MT
1.9V
NQ
NR
NS
NT
2.0V
OQ
OR
OS
OT
2.1V
PQ
PR
PS
PT
Table 3. Factory-Trimmed VCC Reset
Threshold Levels
Table 4. VCC Reset Timeout Period Suffix
Guide
ACTIVE TIMEOUT PERIOD (ms)
PART NO.
SUFFIX
(_)
VCC NOMINAL
RESET
THRESHOLD (V)
TIMEOUT
PERIOD SUFFIX
MIN
MAX
D3
150
300
T
3.075
D7
1200
2400
S
2.925
R
2.625
Z
2.313
Y
2.188
W
1.665
V
1.575
DC-to-DC Converter Application
The MAX6441/MAX6442 triple-output battery monitors
can be used in conjunction with a DC-to-DC converter
to power microprocessor systems using a single Li+
cell or two to three alkaline/NiCd/NiMH cells. The LBOH
output indicates that the battery voltage is weak, and is
used to warn the microprocessor of potential problems.
Armed with this information, the microprocessor can
reduce system power consumption. The LBOL output
indicates the battery is empty, and system power
should be disabled. By connecting LBOL to the SHDN
pin of the DC-to-DC converter, power to the microprocessor is removed. Microprocessor power does not return
until the battery has recharged to a voltage greater than
VLTH+ (see Figure 7).
______________________________________________________________________________________
11
MAX6439–MAX6442
Table 1. Factory-Trimmed Lower and Upper Threshold Combinations for Single-Cell Li+
or Three-Cell Alkaline/NiCd/NiMH Applications
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
Selector Guide
OPEN-DRAIN
RESET
PUSH-PULL RESET
SINGLE LOWBATTERY OUTPUT
DUAL LOW-BATTERY
OUTPUT
MAX6439
X
—
X
—
MAX6440
—
X
X
—
MAX6441
X
—
—
X
MAX6442
—
X
—
X
PART
Typical Application Circuit
Standard Versions Table
PART
TOP MARK
MAX6439UTDHRD3
ABMN
MAX6439UTDHSD3
ABMO
MAX6439UTEHRD3
ABMP
MAX6439UTEHSD3
ABMQ
MAX6439UTEIRD3
ABMR
MAX6439UTEISD3
ABMS
MAX6440UTDHRD3
ABMT
MAX6440UTDHSD3
ABMU
MAX6440UTEHRD3
ABMV
MAX6440UTEHSD3
ABMW
MAX6440UTEIRD3
ABMX
MAX6440UTEISD3
ABMY
DC/DC
Li+
3.6V
VCC
VCC
LBO
MR
NMI
µP
MAX6439
MAX6440
VBATT
RESET
RESET
GND
MAX6441KADHRD3
AEEI
MAX6441KADHSD3
AEEJ
MAX6441KAEHRD3
AEEK
MAX6441KAEHSD3
AEEL
MAX6441KAEIRD3
AEEM
MAX6441KAEISD3
AEEN
MAX6442KADHRD3
AEEO
GND
MAX6442KADHSD3
AEEP
MR
MAX6442KAEHRD3
AEEQ
MAX6442KAEHSD3
AEER
MAX6442KAEIRD3
AEES
MAX6442KAEISD3
AEET
GND
Pin Configurations (continued)
TOP VIEW
VBATT 1
2
3
MAX6441
MAX6442
LBOLH 4
8
VCC
7
LBOL
6
LBOH
5
RESET
SOT23-8
Chip Information
TRANSISTOR COUNT: 1478
PROCESS: BiCMOS
12
______________________________________________________________________________________
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
6LSOT.EPS
PACKAGE OUTLINE, SOT 6L BODY
21-0058
G
1
1
______________________________________________________________________________________
13
MAX6439–MAX6442
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
SEE DETAIL "A"
b
CL
E
MIN
MAX
A
A1
A2
0.90
0.00
0.90
1.45
0.15
1.30
b
0.28
0.45
C
D
E
0.09
2.80
2.60
0.20
3.00
3.00
SYMBOL
e
CL
CL
E1
E1
1.50
L
0.30
L2
e
PIN 1
I.D. DOT
(SEE NOTE 6)
SOT23, 8L .EPS
MAX6439–MAX6442
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
1.75
0.60
0.25 BSC.
0.65 BSC.
1.95 REF.
0∞
8∞
e1
0
e1
D
C
CL
L2
A
A2
GAUGE PLANE
A1
SEATING PLANE C
0
L
NOTE:
1. ALL DIMENSIONS ARE IN MILLIMETERS.
2. FOOT LENGTH MEASURED FROM LEAD TIP TO UPPER RADIUS OF
HEEL OF THE LEAD PARALLEL TO SEATING PLANE C.
3. PACKAGE OUTLINE EXCLUSIVE OF MOLD FLASH & METAL BURR.
4. PACKAGE OUTLINE INCLUSIVE OF SOLDER PLATING.
DETAIL "A"
5. COPLANARITY 4 MILS. MAX.
6. PIN 1 I.D. DOT IS 0.3 MM ÿ MIN. LOCATED ABOVE PIN 1.
7. SOLDER THICKNESS MEASURED AT FLAT SECTION OF LEAD
BETWEEN 0.08mm AND 0.15mm FROM LEAD TIP.
8. MEETS JEDEC MO178.
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, SOT-23, 8L BODY
APPROVAL
DOCUMENT CONTROL NO.
21-0078
REV.
D
1
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
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